Origin and Growth of Carbonate Banks in South Florida
- C. L. V. Monty,
- D. W. J. Bosence,
- P. H. Bridges and
- B. R. Pratt
Published Online: 14 APR 2009
Copyright © 1995 The International Association of Sedimentologists
Carbonate Mud-Mounds: Their Origin and Evolution
How to Cite
Wanless, H. R., Cottrell, D. J., Tagett, M. G., Tedesco, L. P. and Warzeski, E. R. (1995) Origin and Growth of Carbonate Banks in South Florida, in Carbonate Mud-Mounds: Their Origin and Evolution (eds C. L. V. Monty, D. W. J. Bosence, P. H. Bridges and B. R. Pratt), Blackwell Publishing Ltd., Oxford, UK. doi: 10.1002/9781444304114.ch16
- Published Online: 14 APR 2009
- Published Print: 17 JUL 1995
Print ISBN: 9780865429338
Online ISBN: 9781444304114
- associations - obscured-migration or expansion of marine banks;
- Rooting, pelleting, bioturbation associated with seagrass stabilization;
- ‘Caesar's Creek Bank’;
- Gradual (fairweather) allochthonous and autochthonous sediment accumulation occurs;
- Layered mudstone to fine-grained packstone;
- peloidal wackestones to grainstone;
- autochthonous skeletal rudstones to mudstones
Carbonte banks in, and on the margins of, Florida Bay and Biscayne Bay, south-east Florida, are intimately associated with either pre-existing limestone topography (submerged ridges and channel passes through emergent ridges) or transgressed ridges of coastal peat and coastal storm-levee buildups. These associations may be obscured by subsequent migration or expansion of the marine banks and by subsequent transformation of the initiating coastal deposits to marine deposits by repetitive alternations of excavation of marine burrow networks and storm infilling of networks with marine sediment.
Carbonate banks in south-east Florida contain four depositional facies and two early diagenetic facies, each of which shows great textural and compositional variation depending on setting.
On bank interiors and on flanks in protected settings, layered mudstone to wackestone units 0.1–1.2 m in thickness (with or without a grainstone base) are the dominant bank building facies; peloidal wackestones to packstones form in areas of persistent stabilization by seagrass; autochthonous biogenic deposits of calcareous algal grainstones (Halimeda opuntia) to mudstones (Acetabularia) occur with increased circulation and light during shoaling; and sorted grainstones to rudstones cap bank interior areas and represent frequent reworking associated with shallowing to the intertidal zone.
On exposed bank-margin settings, fining-upwards units (0.1–1 m thick) of layered rudstone to fine grainstone are the dominant bank-building facies forming onbank and offbank tempestite lobes; current-baffling and sediment-trapping by seagrass communities generate fine-grained skeletal and peloidal grainstones in areas not catastrophically smothered or eroded by frequent storms; autochthonous coralgal rudstones on bank flanks and channel margins form in areas of increased agitation associated with bank shoaling; and sorted grainstones to rudstones represent frequent reworking associated with higher-energy flanks.
Early diagenetic modification partially to completely transforms depositional facies into two additional facies. Rooting, pelleting and bioturbation associated with seagrass stabilization can transform the upper 50 cm of a sequence into an organic-rich, more peloid-rich packstone. Repetitive excavation of deep open burrow networks and storm infilling of networks with mud-poor packstones can result in partial to complete destruction of depositional facies and replacive generation of new sedimentary fabrics, enhanced porosity and permeability, modified sediment composition and a changed diagenetic and dolomitization potential. Burrow transformation reaches 1–2 m beneath the sediment surface and is the dominant influence on the preserved facies in the broad interior (core) and protected flanks to most banks, where the surface is gradually accreting.